#!/bin/bash
H=`date +%H`
M=`date +%M`
(( time_now=$H*60+$M ))
(( class_over=17*60+30 ))
(( timea=$time_now-$class_over ))
(( timeb=$class_over-$time_now ))
if (( $time_now<$class_over ));then
	echo "距离下课有:`echo "$timeb/60" |bc`小时$(( $timeb % 60 )) minute放学"
elif (( $time_now==$class_over ));then
	echo "现在下课"
else
	echo " 已下课$(( $timea/60 )) 小时 $(($timea% 60  ))  minute"
fi
